Research topics in public administration, dispute resolution, and community development can be very interdisciplinary in nature and therefore there really isn't one "best database" to search. Instead, it is recommended you start your research by using a multidisciplinary search tool like the Library's main search tool, Library Search, or Google Scholar. This will help you get a sense of the literature that exists on your topic, both from within the Library's collection, as well as what's available on the open Internet.
Beyond Library Search and Google Scholar, the Library does have a large number of smaller disciplinary journal article databases that are listed as "best bets" for public administration and related topics, which you can also explore.
If you are unfamiliar with terminology or a topic, a dictionary or encyclopedia can be a good place to start as they can help orient you to the literature. Encyclopedias are particularly useful as they will often include a bibliography of seminal works in the area. Below are just a few examples of these resources. To find more like this, use the Summon search tool and then filter your search to the 'Content Type' --> Reference